Hydraulically actuated pressure foot for wood grinders



Dec. 22, 1959 H. H. BOJE ETAL 2,918,039

HYDRAULICALLY ACTUATED PRESSUREFOOT FOR WOOD GRINDERS 2 Sheets-Sheet 1Filed Aug. 14, 1957 INVENTOR HERBERT H. BOJE AUGUST SCHULZ ATTORNEY Dec.22, 1959 H. H. BOJE 'ETAL 2,918,039

HYDRAULICALLY ACTUATED PRESSURE FOOT FOR WOOD GRINDERS 2 Sheets-$heet 2Filed-Aug. 14, 1957 INVENTOR HERBERT H. BOJE AUGUST SCHULZ ATTORNEYPatented Dec. 22, 1959 HYDRAULICALLY ACTUATED PRESSURE FOOT FOR WOODGRINDERS Herbert H. Boje and August Schulz, Lancaster, Pa., as-

signors to Armstrong Cork Company, Lancaster, Pa., a corporation ofPennsylvania Application August 14, 1957, Serial No. 678,220

8 Claims. (Cl. 121-1) This invention relates to a hydraulic power unitfor a pressure member and is concerned more particularly with ahydraulically actuated pressure foot for wood grinders.

Water is most frequently used as the hydraulic fluid for actuation ofthe pressure foot of wood grinders principally because of thepossibility of leakage of other fluids, such as oil, contaminating thestock of wood fibers which are ground. Leakage in hydraulic-power unitsmost frequently occurs at the packing joint between the piston and theend bell of the cylinder through which the piston rod passes. Thisfailure at the joint packing is due quite frequently to the massiveunbalanced weight of the pressure foot which is supported on the end ofthe piston rod and is disposed at a substantial angle, generally 90, tothe axis of the piston rod and in a substantially vertical or slightlyinclined plane. This unbalanced weight of the foot sometimes causes thepacking to fail, and leakage occurs. With a conventional hydraulicactuated pressure foot, using water as the actuating fluid;

minor leaks are of no consequence, for the water which may get into theground stock is not objectionable. Where oil is used, however, seriousstock contamination may result from even minor packing failures.

Efforts have been made to overcome this leakage problem, and onesolution is to support the pressure foot independently of the power unitso as to avoid the unbalanced weight and the problems which result fromit. This may be accomplished by mounting the pressure foot on a sleevewhich is slidable axially in suitable bearings. A compact unit may beprovided by disposing the hydraulic power unit within the supportingsleeve.

One of the problems with this type of unit is the difficulty of makingrepairs to the actuating cylinder and piston power unit where much ofthe mechanism is mounted within the sleeve which is closed at itsforward end by the pressure foot. The mechanism is quite massive in aconventional wood grinder for forming pulp for fiberboard manufacture,for instance, and may weigh several tons.

An object of the invention is to provide a fluid actuated power unit inwhich the actuated member, such as the pressure foot of a wood grinder,is supported and guided for its movement independently-of the actuatingmember, such as an oil hydraulic cylinder and piston motor, and in whichthe actuating member is arranged for convenient removal from theactuated member.

Another object of the invention is to provide a fluid actuated powerunit in which the actuating member, such as the oil hydraulic cylinderand piston unit referred to above, is received within a sleeve whichsupports the actuated member, such as the pressure foot mentionedpreviously, during movement of the pressure foot, and in which thepressure foot is removably secured to the hydraulic power unit byfastening means which are readily accessible outboard with respect tothe sleeve so that the hydraulic power unit may be removed from withinthe sleeve for repairs without removing the pressure foot from thesleeve.

Other objects of the invention will be clear from the followingdescription of an embodiment of the invention which will be described inconjunction with the attached drawing, in which;

Figure l is a longitudinal cross sectional view of a hydraulicallyactuated pressure foot mechanism for a wood grinder, with the grindingstone shown diagrammatically;

Figure 2 is an end view, partly in section, showing the outboard end ofthe power unit of Figure 1;

Figure 3 is a longitudinal sectional view of the hydraulic power unit ofFigure 1, partially broken away, and drawn to a somewhat larger scalethan Figure 1, illustrating the actuating mechanism partially removedfrom within the pressure foot guiding sleeve;

Figure 4 is an end view of the power unit looking toward the pressurefoot, a portion of which is shown in this view; and

Figure 5 is a sectional view taken along the line VV of Figure 3.

The unit includes a grinding stone 2, a wood pocket 3, i

and a pressure foot 4 which is movable through the pocket 3 to pressbolts of wood received in the pocket into engagement with the stone 2.The foot 4 is actuated by a fluid pressure power unit 5 mounted within ahousing 6. The housing 6 is supported upon a stand 7. A hopper 8 for thereception of bolts of wood to be ground is mounted above the pocket 3and is closed at the bottom by a retractable gate 9 which may beactuated by a fluid pressure power unit 10.

The pressure foot 4 is supported for its reciprocatory movementindependent of the power unit 5. This is accomplished by mounting thefoot 4 on a cylindrical sleeve 11 which is received within housing 6 andis axially slidable with respect to it. The sleeve 11 has an annularmounting flange 12 welded onto its lower end, as shown in Figures 1 and3, and the pressure foot.4 is bolted to this flange by bolts 13, asshown in Figures 4 and 5. The pressure foot 4 may be bored to receivethe sleeve 11, and an annular supporting flange 14 may be provided onthe pressure foot 4 surrounding the end of the sleeve 11, as shown inFigures 1 and 3.

The sleeve is guided for axial movement in a lower bearing 15 mounted inhousing 6 and engageable with a machined surface 16 on the sleeve 11 andan upper bearing 17, which is carried by the sleeve 11 and slides alonga machined inner cylindrical surface 18 in the housing 6. Oil seals 19are provided to engage and seal against the machined surface 16 of thesleeve and are clamped against bearing 15 by a holding ring 20 securedto the housing 6. Similar seals 21 are provided to engage and sealagainst the machined surface 18 of the housing 6. These seals areclamped against bearing 17 by a holding ring 22 secured to sleeve 11.

The power unit 5 includes a cylinder 23 in which a piston is movableunder the action of fluid, such as oil, applied under pressure. Thiscylinder and piston unit usuallyis a double acting power motor arrangedto move the pressure foot 4 to bring bolts of wood deposited in pocket 3into gripping relationship with rotating grinding stone 2 and then topress the bolts of wood into engagement with the stone under substantialpressure during grinding. The unit preferably is constructed so that thepressure foot 4 may be rapidly retracted upon completion of the grindingcycle and also arranged and controlled so that movement of the pressurefoot into gripping position also may be eifected rapidly.

The end bell 24 of the power unit has a clevis connection 25 formedthereon which cooperates with a tongue 26 which projects from end cap 27of the housing 6. The end cap 27 is secured to a flange 28 on housing 6by bolts 29. A clevis pin 30 connects the members 25 and 26 throu h aball and socket connection 31 to provide for self adjustment of thepower unit during movement of the sleeve 11.

Pistonrod 32 of the power unit has a threaded end 32' which is receivedwithin a threaded clevis connection 33. A mounting plate 34 is providedwhich has a tongue 35 welded thereon which cooperates with the clevisconnec tion 33, and a clevis pin 36 and a ball and socket connection 37similar to the connection at the opposite end of the power unit areprovided to join the power unit to the mounting plate.

The mounting plate 34 is provided with a locating boss 38, and thepressure foot 4 is provided with a locating recess 39 for cooperationtherewith. The mounting flange 12'attached to the sleeve 11 is recessed,as shown in Figure'5, to receive the ends of the plate 34; and fasteningrods 40'and 41 of high tensile strength steel pass through openingsprovided in the plate 34 and are threaded into openings provided in thepressure foot 4, as shown in Figure 3.

The mounting plate 34 is secured to the foot 4 through the fastening andguiding rods 4i) and 41 by the use of seamless steel'tube spacer members42 and 43 which are received over the rods 40 and 41. The ends of therods are threaded (Figure l), and nuts 4-4 and 45 clamp the members 42and 43 against the mounting plate 34.

The cap 27 of housing 6 is provided with openings 46 and 47 (Figure 3)covered by dust caps 48 and 49, as shown in Figures 1 and 2. Theopenings 46 and 47 provide access to the nuts 44 and 45 (Figure 1 whichmay be removed with the aid of a socket wrench inserted through theopenings in the end cap.

The usual fluid pressure supply lines 50 and 51 for the power unit passthrough the end cap 27, as shown in Figure 2, and are attached at theend bells of the power unit in the usual way, as indicated in Figure l.

A guiding plate 52 may be positioned over the holding ring 22, as shownin Figure 3, and may be secured to sleeve 11 by cap screws 53. The plate52 is bored to receive the tubes 42 and 43 which surround the rods 49and 41 and will serve to hold these members against whipping andmisalignment during removal of the power unit from within the sleeve 11and reassembly of the power unit within the sleeve 11.

The power unit and the associated mechanism may be removed from withinthe sleeve 11 in the manner indicated in Figure 3 Where the unit isshown in a partially retracted position. The cover caps 48 and 49 arefirst removed, and the nuts 44 and 45 are unscrewed from the rods 40 and41. The bolts 29 which secure the end cap 27 to the housing are alsoremoved. Suitable lifting and retracting equipment, such as a chainhoist mounted on a trolley, is connected to end cap 27; and the powerunit which is'attached to the end cap 24 and carries the mounting plate34 is retracted axially from within sleeve H. The rods 4% and 41 serveas guides during removal of the unit, the guiding plate 52 supportingthe rods All and 41. When the unit is retracted to a position where themounting-plate 34 is adjacent to the guiding plate 52, the cap screws 53may be removed and the guiding plate retracted, permitting'the unitincluding the guiding plate 52 to pass from within the sleeve 11 and outof engagement with the rods 49 and 41.

When the unit is to be reinserted, the mounting plate 34 is positionedover the rods it? and 4 and the unit is guided into position, theguiding plate 52 is secured in position, and the unit is guideddownwardly until the lecating boss 38 of the mounting plate 34 is fittedinto the guiding and aligning recess 39 in the pressure foot 4. The nuts44 and 45 are then applied and drawn down firmly, connecting themounting plate 34 to the pressure foot 4 and thereby connecting thepower unit 5 to the pressure foot for actuation. The bolts 29 arereinserted, connecting the cover cap 27 to housing 6, and fixing thecylinder 23 in position through the clevis connection to the end bell 24of the power unit.

The fastening rods 40 and 41 are of adequate size to withstand the forceof the power unit, should through some accident a bolt of wood becomelodged between the rear surface of the pressure foot and the housingduring retraction of the pressure foot.

The unit of this invention is so constructed and arranged that, shouldthere be failure of the packings or other damage which may requireremoval of the power unit for repairs, such removal may be effectedconveniently from the outboard end of the unit without dismantling thepressure foot and sleeve assembly. The hydraulic oil or other hydraulicfluid which might contaminate the stock, should a leak occur, is sealedagainst passage into the wood pocket; and thus the possibility ofcontamination is reduced to a minimum, making the use of an oilhydraulic system practicable for commercial wood pulp grinding.

We claim:

1. In a pressure member including a housing, a sleeve slidable withinthe housing, an actuated member connected to the sleeve, and a fluidpressure actuated power unit received within the sleeve for actuatingsaid member, the combination of a mounting plate received within saidsleeve and connected to one end of said power unit, a holding memberconnected to the other end of said power unit, connecting means securingsaid holding member to said housing, and means accessible from theoutboard end of said sleeve with said holding member connected to saidhousing for removably securing said mounting plate to said actuatedmember.

2. In a pressure member including a housing, a sleeve slidable withinsaid housing, and an actuated member connected to said sleeve formovement with it, the combination of a power unit demountably receivedwithin said sleeve and comprising a fluid actuated piston and cylindermotor, a mounting plate received within said sleeve and connected to oneof said piston and cylinder, a holding member connected to the other ofsaid piston and cylinder and to said housing, and means passing axiallythrough said sleeve and accessible with said holding member connected tosaid housing for removably securing said mounting plate to said actuatedmember.

3. In a pressure member including a housing, a sleeve slidable withinsaid housing, and an actuated member connected to said sleeve formovement with said sleeve, the combination of a power unit demountablyreceived within said sleeve and comprising a fluid actuated piston andcylinder motor, a mounting plate received within said sleeve andconnected to one of said piston and cylinder, a holding member connectedto the other of said piston and cylinder and to said housing, aplurality of guide rods received within said actuated member and passingthrough said mounting plate and extending axially through'said sleevefor supporting and guiding said power unit' in assembly and disassemblywithin said sleeve, and means accessible with said holding memberconnected to said housing for removably joining said mounting plate tosaid actuated member for movement in unison by said power unit.

4. In a pressure member including a housing, a sleeve slidable withinsaid housing, and an actuated member connected to said sleeve formovement with said sleeve, the combination of a power unit demountablyreceived within said sleeve and comprising a hydraulic piston andcylinder motor, a mounting plate received within said sleeve andconnected to one of said piston and cylinder, a holding member connectedto the other of said piston and cylinder and to said housing, aplurality of guide rods received within said actuated member and passingthrough said mounting plate and extending axially through said sleevefor supporting and guiding said power unit in assembly and disassemblywithin said sleeve, and means accessible with said holding member.

gamma connected to said housing for removably joining said mountingplate to said actuated member for movement in unison by said power unit,said last named means comprising clamping means received on said rodsand spacer tubes disposed between said mounting plate and said clampingmeans.

5. In a pressure member including a housing, a sleeve slidable withinsaid housing, and an actuated member connected to said sleeve formovement with said sleeve, the combination of a power unit demountablyreceived within said sleeve and comprising an oil-hydraulic piston andcylinder motor, a mounting plate received within said sleeve andconnected to one of said piston and cylinder, a holding member connectedto the other of said piston and cylinder and to said housing, aplurality of guide rods received within said actuated memher and passingthrough said mounting plate and extending axially through said sleevefor supporting and guiding said power unit in assembly and disassemblywithin said sleeve, a'plurality of spacer tubes received over said rods,guiding means for said rods and tubes disposed adjacent to the outboardend of said sleeve, and means accessible from the outboard end of saidpower unit with said holding member connected to said housing forremovably joining said mounting plate to said actuated member formovement in unison by' said power unit.

6. In a pressure member including a housing, a sleeve slidable withinsaid housing, and an actuated member connected to said sleeve formovement with said sleeve, the combination of a power unit demountablyreceived Within said sleeve and comprising a hydraulic piston andcylinder motor, a mounting plate received within said sleeve andconnected to one of said piston and cylinder, a holding member connectedto the other of said piston and cylinder and to said housing, aplurality of guide rods received within said actuated member and passingthrough said mounting plate and extending axially through said sleevefor supporting and guiding said power unit in assembly and disassemblywithin said sleeve, a plurality of spacer tubes received over said rods,guiding means for said rods and tubes, means re-' movably securing saidguiding means to said sleeve, and clamping means on said rods accessiblewith said hold- 6 slidable within said housing, and an actuated memberconnected to said sleeve for movement with said sleeve, the combinationof a power unit demountably received within said sleeve and comprising afluid actuated piston and cylinder motor, a mounting plate receivedwithin said sleeve and connected to said piston, an end cover connectedto said cylinder and to said housing, a plurality of guide rods receivedwithin said actuated member and passing through said mounting plate andextending axially through said sleeve for supporting and guiding saidpower unit and mounting plate in assembly and disassembly within saidsleeve, a plurality of spacer tubes received over said rods, guidingmeans for said rods and tubes removably secured to said sleeve, andclamping ing member connected to said housing for removably joining saidmounting plate to said actuated member for movement in unison by saidpower unit.

7. In a pressure member including a housing, a sleeve nuts received onsaid rods and accessible through openings in said end cover for clampingsaid mounting plate to said actuated member through said spacer tubes.

8. In a hydraulically actuated pressure foot for wood grinders includinga housing, a sleeve slidable within said housing, and a pressure footconnected to said sleeve for movement with said sleeve, the combinationof a power unit demountaoly received within said sleeve and comprising ahydraulic piston and cylinder motor, a mounting plate received withinsaid sleeve and connected to one of said piston and cylinder andarranged to be clamped to said pressure foot, an end cover connected tothe other of said piston and cylinder and secured to the outboard end ofsaid housing, a plurality of guide rods received within and secured tosaid pressure foot and passing through said mounting plate and extendingaxially through said sleeve and a portion at least of said end cover forsupporting and guiding said power unit in assembly and disassemblywithin said sleeve, and means accessible with said end cover connectedto said housing for removably joining said mounting plate to saidpressure foot for movement in unison by said power unit, said last namedmeans comprising a plurality of spacer tubes received over said rods,and clamping nuts received on said rods and pressing said spacer tubesinto engagement with said mounting plate to join said mounting plate tosaid pressure foot.

References Cited in the file of this patent UNITED STATES PATENTS1,623,936 Colley Apr. 5, 1927 1,905,224 Haas et al. Apr. 25, 19332,422,210 Reischl June 17, 1947

